From Angra D, organic preservation was noted from several areas. A small quantity of organic material was sampled from a complete bucket on the mast step (S39b) (Fig. 2, Fig. 3), In addition, insect remains from the base of the bucket, visible with the naked eye, were collected. From Angra C what was thought to be a layer of seeds from under decking planks (S139b) (Fig. 2) was sampled. The organic residues were sorted under a stereomicroscope. The insect material which was well preserved was identified to the lowest taxonomic level using modern comparative specimens and entomological keys. Lack of taxonomic knowledge and the fragmented nature of the material prohibited identifications to the lowest taxonomic level in some cases. Insect data from other late medieval shipwreck were collated and compared with the faunas from Angra D and Angra C in order to understand better the role of these seventeenth century vessels in the introduction of exotic insect species.
The insect assemblages
The assemblage from Angra D (S39b) and Angra C (S139b) show strong similarities. In essence, Angra C includes a sub-set of taxa (with 4 taxa and 8 individuals), in comparison with Angra-D (12 taxa and 155 individuals), and fewer specimens (See Table 1). The most abundant taxon from Angra D is tentatively referred to the ephydrid genus Paracoenia. These flies are found from a variety of foul aquatic contexts, including mineral or hot springs, alkaline lakes, and in areas with saline water (Mathis 1975). Paracoenia fumosa (Stenhammar) breeds in rich organic mud, often on midden edges. As other ephydrids, it has been associated with yeast (Maksimova et al. 2020) and has not previously been recorded in fossil synanthropic assemblages. However the puparia of the genus have not been adequately described, and the present identification to P. fumosa relies mainly on the presence of (inter alia) a very strong apicoventral spur on the mid-tibiae of the adult.
Another ephydrid from both shipwrecks is Scatella. The genus is associated with algae (Foote 1977) which would have been found in abundance within the environments of medieval vessels. In the case of Angra C, in addition to Scatella sp., there is evidence for Scatella (Teichomyza) fusca (Macquart), an ephydrid which is associated with urine, dung and faeces (Vogler 1900, Vibe Petersen 1998) and hence it has earned the common name urine fly. Its larvae thrive on urine-soaked wood of ancient buildings (Foote 1995) and its pupae can block sewage pipes and drains (Smith, 1989, Vibe Petersen 1998). Adults have been described during winter and in addition to its European records, it has been described from western South America. Although there is no consensus as to whether it is neotropical (Mathis 1980) or Palaearctic, shipped from Europe to the Americas (Wirth 1968), its presence from Angra C could perhaps argue for its transport from Europe via maritime routes.
Piophila casei L. is a cosmopolitan species which oviposits on cheeses, dry meat, smoked fish and can also be found in carrion (Merritt et al. 2009). It is associated with forensic cases and can be an important forensic indicator as it colonises corpses during caseous fermentation (Martin-Vega 2011). Megnin (1894) noted its association with caseic fermentation in corpses and he detailed observation of its larvae jumping from a corpse, this leaping behaviour and its association with some types of cheese, where the larvae breed, has led to its common name cheese skipper. It has been implicated in cases of urinary myiasis (Saleh and el Sibae 1993) and intestinal infections by P. casei are a direct result of a consumption of food infested by this fly for example salted fish, cured meat, etc. (Zumpt 1965). The earliest records of P. casei come from a Greco-Roman Egyptian mummy (Curry 1979, Panagiotakopulu unpublished), suggesting a north African origin.
Several species of Hydrotaea, formerly referred to the genus Ophyra, are strongly synanthropic and have been transported widely through human commerce. Originally from the Old World, Hydrotaea capensis (Wiedemann) and Hydrotaea ignava (Harris) are well-known cosmopolitan "filth-inhabiting" synanthropes with a probably ancient association with man. H. capensis has a fourteenth century record from Italy, from the mummy of the Blessed Antonio Patrizi (Morrow et al. 2015), and probably originated in the Mediterranean area, while H. ignava is possibly from further north in Europe. However, another Hydrotaea species, this time of American origin, which appears only recently to have crossed the Atlantic to become established in the Palaearctic, is H. aenescens (Wiedemann). The earliest record from Europe is from refuse dumps in Italy in 1964, spreading to Norway by 1982 (Skidmore 1985). In 2000 it was also taken from a refuse dump at El Sinbillawein in Egypt (Skidmore and El-Serwy, pers. com.). All Hydrotaea species are predatory in the larval stage (Skidmore 1985) And in this sample (Angra D 39b), they were probably feeding on maggots of other flies (Musca domestica, and, possibly, those of ephydrids).
Dohrniphora cornuta (Bigot), a phorid and the most abundant taxon from the shipwrecks, probably originated from sub-tropical or tropical oriental areas (Disney et al. 2009) and has been spread worldwide by commerce. The genus is otherwise restricted to warmer regions. D. cornuta is a filth inhabiting fly (Barnes 1990), recorded from rotting cargoes in ships, including rice bran, cow peas, etc., but is also known from sewage, compost, dead animals (snails, insects, vertebrates etc.). Its larvae are polyphagous but primarily sarcophagous and share the same habitat with adult females, feeding on decaying plants and dead and decaying animal matter Disney 1983, Barnes 1990). One of the most interesting modern records comes from the cargo of a Burmese ship in Liverpool (Colyer unpublished notes in Disney et al. 2014). It has been noted for its synanthropic tendencies, adult females have been observed biting humans (Schmitz 1938, 1951), and it has also been observed living in human excrement (Skidmore 1978). Its larvae have been recorded causing myiasis in cattle (Patton 1922) but not from humans. D. cornuta has been recently recorded from forensic cases and there is a strong possibility that it will become an important forensic indicator in the near future (Disney et al. 2014).
The specific identity of the single incomplete Heleomyza puparium from Angra D cannot be ascertained, but three species, H. captiosa, H. serrata and H. borealis figure extremely prominently in archaeological contexts of Norse settlements in Britain, Iceland and West Greenland (Skidmore 1996, Panagiotakopulu et al. 2007) and it is most likely that they were widely dispersed by ships in the medieval period. Heleomyza spp. are troglodytic and have a strong preference for materials high in protein. They can be necrophagous, although they tend to breed in midden materials and in dung of ominivorous and carjnivorous mammals (Skidmore 1996).
Spelobia spp. is a genus of lesser dung flies which tend to live in subterraneous habitats and are saprophagous, living on rotting substrates (Roháček 2011). Drosophila sp. is another taxon which frequents rotting fruit, decaying plant tissues and their fluxes (Carson 1971).
Amongst the species present on the Spanish ship (Angra D, S39b), this time of certain identity at the species level, is Musca domestica L., the common house-fly, which breeds in fermenting putrescent organic material and is most abundant in the company of man, it is eusynanthropic and is perhaps the most commonly recorded fly throughout the world. Through its effluvia and excreta it can spread mechanically a range of different pathogens, protozoa, bacteria, fungi and viruses. It can cause myiasis and one of the main diseases it is associated with is Chlamydia trachomatis, trachoma, which is endemic in Africa (Greenberg 1973, Brewer et al. 2021). The housefly has originated in the Old World, most probably in the Nile valley (Panagiotakopulu and Buckland 2017) from whence it has been distributed to Europe with early farmers and it later became cosmopolitan (Panagiotakopulu and Buckland 2018). Current research suggests that it was by far the most abundant fly breeding in human settlements in Egypt during Dynastic times, for instance at the Workmens’ village at Amarna during the construction of the tomb of Akhenaten in the fourteenth century BC (Panagiotakopulu et al. 2010). It was presumably taken to the Americas by commerce and this record aboard a seventeenth century ship in the mid-Atlantic is of interest in terms of its biogeography.
Apart from the dipterous material, the sample mainly consisted of fragments of various Coleoptera, including several larval urogomphi of Dermestes sp. and bits of adults of this genus. Its larvae have a capacity to feed on a variety of dried materials from dried meat to skin and bones (Peacock 1993). Also present was a head capsule of a parasitic Hymenopteran, probably belonging to the Diapriidae which are mainly parasitic on larvae of Diptera.
A piece of the tegmen of a cockroach was recovered from the sample, which probably belongs to Periplaneta americana (L.). This was in addition to several wings collected from the base of the bucket, during sampling (Fig. 4). P. americana is a nocturnal pest, sometimes called kakerlac, from the Danish word for cockroach, ship cockroach, Bombay canary (Guthrie and Tindall 1968) or waterbug in America, as a result of its proliferation in New York at the time of the arrival of a piped water supply in 1842 (Johnson 1928). It lives in a variety of different commodities and waste, from cheese, meat, mushrooms to detritus, hair, glue, cloth and dead insects (Bell and Adiyodi 1981). It thrives in humid environments and warm temperatures (Roth 1982) and is found in areas with suitable microclimate, (e.g. wood piles, hollow trees, etc. outdoors, or piped central heating systems, water pipes, sewers, etc., particularly indoors). This insect pest can mechanically spread a variety of different pathogens, and a range of food-borne pathogens such as Escherica coli, Shigella dysenteriae, Staphylococcus aureus, and Salmonella enterica, have been associated from P. americana (Donkor 2020). Although it is called the American cockroach, its origins are thought to lie in tropical West and South Africa, where it is closely related to the African genus Pseudoderopeltis, and there is also an argument for an Indo Malaysian origin (Rhen 1945). The earliest records of its congeners P. japonica of Japanese origin and the synanthropic P. fuliginosa, of Asian origin, come from imprints on Jomon pottery, as early as 5300 years ago for the former and 4800-4000 years ago for the latter (Obata et al. 2022). P. americana appears for the first time from the shipwreck of the Spanish galleon San Esteban on Padre Island, Texas, in 1554 (Durden 1978), and there are additional records of the “American” cockroach from other shipwrecks from the sixteenth and the seventeenth century (see discussion below). It now has a cosmopolitan distribution and is perhaps the most common cockroach in houses in the United States (Cornwell 1976).